Water is employed in a wide range of industrial processes and for a wide range of purposes, each of which imposes its own requirements or characteristics on the properties of the water entering and discharged by the process. Such requirements on the properties or characteristics of water used in or discharges from various processes in turn often result in water treatment processes necessary to make the water suitable or acceptable for use in or discharge from the process, and the various water treatment processes in themselves may be a major technical or economic component of an industrial process.
Various industrial processes can impose a number of chemical and physical requirements on incoming water, such as acidity, salinity, temperature and so on, and corresponding requirements on discharge water, typically to meet environmental or health requirements. In many commonly found industrial processes, however, the principle requirements for input and discharge water concern the particulate or suspended contents of the water rather than, for example, the chemical or dissolved contents of the water.
Examples of processes in which the physical or mechanical contents of the intake and discharge water are the primary concern are found in the stone fabrication industry, such as those involved in cutting, shaping and polishing natural and man-made stone for such products as countertops, flooring, architectural paneling, and so on. As is well known by those of ordinary skill in these arts, water is commonly used to wash away the particulate waste material from the cutting and polishing processes, as a coolant to carry off heat produced by the processes, and often as a lubricant. As a consequence, stone cutting and polishing processes, whether of natural stone or man-made stone-like materials, generate heat and significant volumes of particulate waste material, both of which are carried away in and by the process discharge water. The discharge water is consequently referred to as “grey” water, because of the particulate waste material in the water. The particulate water material is primarily comprised of the material being cut or polished, but will often include other particulate material, such as particles from the cutting and polishing tools themselves and polishing or cutting compounds used with the tools and processes.
The type and degree of treatment performed on the grey discharge water from the processes depends, in turn, on what is done with the discharge water. For example, the grey water is eventually discharged from the processes and the treatment of the grey water before final discharge may be dictated by environmental or health factors. In some instances, the grey water may be treated in no more than a “settling tank” to allow at least some of the particulate waste to “settle out” as sediment before the water is returned, for example, to a river or discharged to enter the groundwater. In addition, water discharged into rivers, streams, groundwater and so on is required to meet state and federal requirements, which typically require ongoing random testing of the discharged water. In most instances, environmental or health concerns may require removal of the particulate waste to the level of “crystal clear” water, as discussed below, before it is returned to the environment or original source.
In still other instances, at least some of the grey water may be recycled to the processes as intake water, thereby reducing to total water volume requirements of the processes. The treatment of recycled grey water will depend, however, upon the uses to which the grey water is to be put. For example, certain processes, and in particular stone cutting, drilling and cooling processes, may use grey water containing a significant amount of particulate waste as the particulate waste from a previous cycle through a stone cutting or polishing and Computer Numeric Controlled (CNC) process will not adversely effect a cutting, drilling, cooling or coarse grinding process. In such instances, the recycled grey water may require no more than a settling tank to allow sedimentation of enough of the particulate waste material that the remaining waste material does not “clog” the ensuing process in which it is used, or may require no treatment at all.
In other instances, however, the process or processes receiving recycled water require “crystal clear” water, that is, water in which the volume and size of particulate matter is strictly limited. Stone polishing and CNC processes, for example, must use intake water that is “crystal clear”, that is, water that generally contains no particulate matter, except particles that are generally less than 2 microns in diameter, as larger particulate matter will interfere with the polishing or CNC process by making and leaving scratches that will prevent the desired degree of polish or finish, that may leave visible scratches and that may clog the polishing tools and CNC spindle.
The recycling of grey water into “crystal clear” water, however, is a technically and economically more complex and expensive process than a sedimentation tank as used to recycle grey discharged water to grey intake water for such processes as cutting, drilling, cooling and coarse grinding, and the choice is subject to many factors. For example, it may be less expensive to provide fresh intake water for those processes requiring “crystal clear” water, and to treat all discharge water as grey water for both discharge and recycling purposes. In the alternative, however, and very often, the required quantities of fresh intake water, or intake water of sufficient quality, may not be available or may be more costly than cleaning and recycling grey water into crystal clear water, or the volume of grey water that may be discharged may be limited for any of a number of reasons.
The problem, therefore, is to provide an environmental water discharge system for industrial processes such as stone cutting, grinding, cooling, polishing and for CNC equipments that reduces the required volume of fresh intake water and eliminates all grey discharge water by economic and efficient recycling of grey water into crystal clear water in the required quantities.
The present invention addresses and provides a solution for these and other related problems of the prior art.